Purification of unactivated progesterone receptor and identification of novel receptor-associated proteins.
Progesterone receptor complexes were purified from crude cytosol in a rapid, gentle, one-step procedure using anti-receptor monoclonal antibodies covalently attached to an agarose resin. Five nonreceptor proteins specifically co-purified with unactivated avian progesterone receptor; these proteins had molecular masses of approximately 90, 70, 54, 50, and 23 kDa. The 90- and 70-kDa proteins have been previously identified as the 90-kDa heat shock protein and a member of the 70-kDa heat shock protein family, respectively. The 54-, 50-, and 23-kDa proteins have not been previously described as associated with avian progesterone receptor. Two-dimensional gel electrophoresis revealed charge heterogeneities for all five proteins. Except for p70, each could be dissociated from receptor by salt, a process inhibited by sodium molybdate. However, molybdate was not required for protein association with receptor in low ionic strength. Following progesterone treatment in vivo p70 still co-purified with cytosolic receptor although the other affiliated proteins were reduced, suggesting hormone-dependent dissociation in conjunction with receptor activation. One of the proteins, p54, displayed in vitro hormone-dependent dissociation which was not prevented by molybdate.
Smith
D F
DF
Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905.
Faber
L E
LE
Toft
D O
DO
D000818:Animals; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D002645:Chickens; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D008970:Molecular Weight; D010057:Oviducts / Q000187:drug effects / Q000378:metabolism*; D011374:Progesterone / Q000494:pharmacology; D011506:Proteins / Q000302:isolation & purification*; D011980:Receptors, Progesterone / Q000096:biosynthesis / Q000302:isolation & purification*
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D011506:Proteins; D011980:Receptors, Progesterone; D011374:Progesterone; D004958:Estradiol